Ignition apparatus, internal-combustion engine, ignition plug, plasma equipment, exhaust gas degradation apparatus, ozone generating/sterilizing/disinfecting apparatus and odor eliminating apparatus

ABSTRACT

A plasma equipment comprising a microwave oscillator for generating a predetermined microwave band, a microwave resonant cavity for allowing the predetermined microwave band to resonate, and microwave radiation means for radiating the microwave into the microwave resonant cavity, wherein the microwave radiation means is a microwave radiation antenna having the shape and the size so as to form a strong electric field of the microwave in a plasma generation field formed by the microwave.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Divisional Application of U.S. patent applicationSer. No. 12/083,608, filed on Apr. 15, 2008 which is a U.S. NationalPhase Application (35 USC 371) of PCT/JP2006/319850, filed on Oct. 4,2006 and claims priority under 35 USC 119 of Japanese Application No.2006-255109, filed Sep. 20, 2006.

The teachings of Japanese Application No. 2006-255109, filed Sep. 20,2006 are incorporated herein in their entirety, inclusive of thespecification, claims and drawings.

FIELD OF ART

The present invention relates to an ignition apparatus used in a heatengine such as a reciprocating engine, a rotary engine, a jet engine anda gas turbine, or a plasma equipment.

The present invention relates to an internal-combustion engine to whichthe ignition apparatus according to the present invention is suitablyapplied.

The present invention relates to an ignition plug that is suitablyapplied to the ignition, apparatus according to the present invention.

The present invention relates to a plasma equipment that is used in anenvironmental (an in-plant and an end-of-pipe) countermeasure field suchas decrease and reduction in hazardous effluents (CO₂, NO_(x), andunburned hydrocarbon), volatile organic compounds (VOC), suspendedparticulate matters (PM), soot and the like or process and reuse of tar,sludge and drainage, and a medical/hygiene field such as sterilization,pasteurization and cleaning technologies.

The present invention relates to an exhaust gas degradation apparatus towhich the plasma equipment according to the present invention issuitably applied.

The present invention relates to an ozonegenerating/sterilizing/disinfecting apparatus and an odor eliminatingapparatus to which the plasma equipment according to the presentinvention is suitably applied.

BACKGROUND ART

In the past, ignition of mixture in an internal-combustion engine suchas a reciprocating engine and a rotary engine was carried out by anignition plug for performing spark discharge. However, there has beensuggested an ignition apparatus that performs ignition usingelectromagnetic wave with frequency of several gigahertzes (GHz), thatis microwave irrespective of the spark discharge, since electromagneticnoise that occurs by the spark discharge causes erroneous operation ofan electronic device mounted on a vehicle.

For example, the ignition apparatuses in which a microwaveguide isconfigured to be connected to a combustion/reaction chamber (in acylinder) and a discharge electrode for making microwave discharge isprovided in the combustion/reaction chamber is disclosed in PatentDocuments 1 to 4.

In the ignition apparatus, microwave pulses generated by a microwavegeneration unit (magnetron) are transmitted through the microwaveguideto the inside of the combustion/reaction chamber and microwave coronadischarge is caused by the discharge electrode to ignite mixture in thecombustion/reaction chamber.

For example, according to Patent Document 5, there is disclosed agasoline internal-combustion engine in which a high frequency electricfield generator (magnetron) is provided in the combustion/reactionchamber (in a cylinder) so that the high frequency electric fieldgenerator forms a high frequency electric field in the combustionchamber during the step of a compression stroke of the engine to performdielectric heat, ignite, and burn mixture in the combustion chamber.

In the conventional plasma equipments used in the environmentalcountermeasure technologies, in general, high-temperature thermalequilibrium plasma is generated by increasing energy input into plasmagenerated by making discharge under low pressure to heat hazardouseffluents, chemical substances, suspended particulate matters, soot andthe like to high temperature so as to oxidize and degrade them.

Recently, a method (coaxial resonator-type plasma generation) ofgenerating atmospheric thermal non-equilibrium plasma by microwavedischarge has been studied. The generated plasma is reactive plasma inwhich temperature of electron is tens of thousands and temperature ofgas is in the range of normal temperature to 1,000° C. In addition, aplasma equipment for a sterilization/disinfecting/odor elimination usedin a medical/hygiene field has been developed by using effect of strongchemical reaction of OH radical, O₃ (ozone), and the like generated bythe plasma (Innovation Japan 2005;http://ccr.ccr.tokushima-u.ac.jp/topic/050927-01.pdf).

A plasma equipment using the microwave allows gas with the pressureclose to the atmospheric pressure to be excited by the microwave so asto generate plasma gas.

For example, a microwave plasma equipment is disclosed in PatentDocuments 6 and 7. In the microwave plasma equipment, a non-metal pipefor a gas flow channel is disposed along the center of a centralconductor, and gases injected from one end are excited by the microwaveat a gap where the non-metal pipe is not covered with the centralconductor, and then are induced plasma (coaxial resonator-type plasmageneration) and discharged from the other end.

-   [Patent Document 1] JP-A-57-186067-   [Patent Document 2] JP-A-3-31579-   [Patent Document 3] JP-A-2000-230426-   [Patent Document 4] JP-A-2001-73920-   [Patent Document 5] JP-A-2000-274249-   [Patent Document 6] JP-A-2001-035692-   [Patent Document 7] JP-A-2004-172044

DISCLOSURE OF THE INVENTION

However, in recent years, it is required to improve fuel consumptionrate in a heat engine such as a reciprocating engine, a rotary engine, ajet engine and a gas turbine, or a plasma equipment. In order to improvethe fuel consumption rate, it may be supposed that fuel ratio of mixtureis decreased and combustion/reaction of the lean mixture is performed.However, when the fuel ratio of the mixture of a conventionalinternal-combustion engine and the like is decreased, stability ofcombustion/reaction is impaired, for example, its cycle fluctuates. As aresult, problems such as output degradation occur.

Accordingly, in order to improve the fuel consumption rate in the heatengine or the plasma equipment, it is necessary to perform the stableand highly efficient combustion/reaction even when the fuel ratio of themixture is decreased and the combustion/reaction of the lean mixture isperformed.

The ignition apparatus using the above-mentioned microwave coronadischarge can be hardly put to practical use, since fuel consumptionrate improvement and stability of the combustion/reaction cannot beexpected comparing with an ignition method using the conventional sparkdischarge.

In addition, in the gasoline internal-combustion engine using theabove-mentioned high frequency electric field generator, the magnetronis directly mounted on the engine, so that there is occurrence ofvarious troubles in terms of durability, vibration resistance,limitations of mounting space, ambient temperature (that is, temperatureof an engine increases), and malfunction prevention of a control systemdue to microwave leakage. For this reason, the gasolineinternal-combustion engine of this kind can be hardly put to practicaluse.

The present invention is therefore contrived in view of theabove-mentioned problems, and its object is to provide an ignitionapparatus capable of achieving improvement of output, exhaust gascleaning, and improvement of fuel consumption rate by performing thestable and highly efficient combustion/reaction even when the fuel ratioof the mixture is decreased and the combustion/reaction of the leanmixture is performed in a heat engine such as a reciprocating engine, arotary engine, a jet engine and a gas turbine, or a plasma equipment.

In addition, an object of the present invention is to provide aninternal-combustion engine capable of solving the various troubles interms of durability, vibration resistance, limitations of mountingspace, and ambient temperature (that is, temperature of an engineincreases), and malfunction of a control system due to microwave leakagecaused when a magnetron is directly mounted on an engine in the gasolineinternal-combustion engine.

An object of the present invention is to provide the internal-combustionengine to which the ignition apparatus mentioned above according to theinvention is suitably applied. In addition, an object of the presentinvention is to provide an ignition plug suitably applied to theignition apparatus mentioned above according to the present invention.

In addition, in a conventional plasma generation method, a great amountof energy is spent in order to continuously generate a high-temperatureplasma, the apparatus itself is very expensive (3,000,000 yen or more),running cost is relatively expensive, and transportation is difficultsince the apparatus itself is large in size. Further, research anddevelopment of a technology using the atmospheric thermal nonequilibriumplasma have been just started. The above-mentioned discharge between thecentral conductors is used for plasma ignition, but large output (in therange of several hundreds of W to 5 kW or so) is still necessary so asto continuously generate stable plasma. At present, in the field of anenvironmental countermeasure technology and an application technologyfor a medical/hygiene field using the plasma equipment, low price isdemanded for product performance of such countermeasure technology. Forexample, price is 300,000 yen or less per unit and electricity expenseis around 30,000 yen per month for a small-size VOC process apparatusprocessing less than 1 ton per year (Ministry of Economy, 2004; chemicalmaterial risk reduction technology objective).

The plasma according to the present invention is microwave plasma oflow-temperature/atmospheric pressure air. In the plasma, hazardouseffluents, chemical substances, suspended particulate matter, soot, andthe like are not heated in high temperature, but are oxidized andreacted chemically by products generated by the plasma (OH radical andozone (O₃)), so that the hazardous effluents and the like is decreased,reduced, and detoxified. The plasma has a totally different novelty andeffectiveness from the conventional technology using the hightemperature plasma. In the past, much energy and a large-sized apparatusare required to generate the plasma for detoxifying the hazardouseffluents. In addition, there has been few low-priced and small-sizedapparatus capable of easily inducing plasma in atmospheric pressure airand generating a great amount of radicals.

For this reason, the present invention is contrived in view of theabove-mentioned circumstance, and its object is to provide a low-pricedand small-sized plasma equipment capable of easily inducing plasma inatmospheric pressure air and generating a great amount of radicals.

Another object of the present invention is to provide the plasmaequipment capable of being applied to not only the end-of-pipecountermeasure technology but the in-plant countermeasure technology.Further, an object of the present invention is to provide the suitableplasma equipment capable of performing stable and highly efficientcombustion in various combustors so that combustion process is improved(energy saving by volumetric ignition and extension of the combustionlimit of lean fuel owing to chemical oxidization and reaction by strongOH radicals) and the hazardous effluents are decreased and reduced bydecomposing and completely burning of unburned fuel without reducingoutput of power.

Still another object of the present invention is to provide an effectiveexhaust gas degradation apparatus, an ozonegenerating/sterilizing/disinfecting apparatus, and an odor eliminatingapparatus by generating a great amount of OH radicals and O₃ that iscontinuously active at low cost.

In order to solve the above-mentioned problems and achieve theabove-mentioned object, an ignition apparatus according to the presentinvention includes any one of the following configurations.

[Configuration 1]

According to an aspect of the invention, there is provided an ignitionapparatus including dielectric constant control means for controllingdielectric constant of mixture in a combustion/reaction field byintroducing water and/or exhaust gas generated from thecombustion/reaction field into the combustion/reaction field wherecombustion/reaction or plasma reaction of the mixture is carried out,the mixture of reactive gas and oxidation gas existing in a heat engineor a plasma equipment; microwave radiation means for radiating microwaveinto the combustion/reaction field so as to increase temperature of themixture in the combustion/reaction field and performing plasma dischargein the combustion/reaction field so as to increase radicalconcentration, so that characteristics of flame ignition is improved andflame propagation speed is promoted; ignition means for igniting themixture in the combustion/reaction field by making discharge; andmicrowave radiation means for making discharge in the mixture in thecombustion/reaction field so as to increase radical concentration incombustion/reaction or plasma gas, so that the characteristics of theflame ignition is improved and the flame propagation speed is promoted,wherein the dielectric constant control means controls the dielectricconstant of the mixture before the combustion/reaction of the mixture iscarried out in the combustion/reaction field so as to allow resonancefrequency of the mixture in the combustion/reaction field to resonatewith frequency of the microwave radiated from the microwave radiationmeans.

[Configuration 2]

According to another aspect of the invention, there is provided anignition apparatus including dielectric constant control means forcontrolling dielectric constant of mixture in a combustion/reactionfield by introducing water and/or exhaust gas generated from thecombustion/reaction field into the combustion/reaction field wherecombustion/reaction or plasma reaction of the mixture is carried out,the mixture of reactive gas and oxidation gas existing in a heat engineor a plasma equipment; microwave radiation means for radiating microwaveinto the combustion/reaction field so as to increase temperature of themixture in the combustion/reaction field and performing plasma dischargein the combustion/reaction field so as to increase radicalconcentration, so that characteristics of flame ignition is improved andflame propagation speed is promoted; ignition means for igniting themixture in the combustion/reaction field by making discharge; microwaveradiation means for performing plasma discharge in thecombustion/reaction field so as to increase radical concentration in thecombustion/reaction field, so that the characteristics of the flameignition is improved and the flame propagation speed is promoted; andcontrol means for controlling the microwave radiation means and theignition means, wherein the microwave radiation means and the ignitionmeans are controlled by the control means so as to repeat a cycle thatis a process by which the microwave radiation means radiates themicrowave into the combustion/reaction field to increase the temperatureof the mixture in the combustion/reaction field and makes the plasmadischarge in the combustion/reaction field to increase the radicalconcentration, so that the characteristics of the flame ignition isimproved and the flame propagation speed is promoted; the ignition meansignites the mixture using the discharge; and then the microwaveradiation means makes the plasma discharge in the combustion/reactionfield by radiating the microwave into the combustion/reaction field toincrease the radical concentration, so that the characteristics of theflame ignition is improved, the flame propagation speed is promoted, andthe combustion/reaction of the mixture is promoted in thecombustion/reaction field.

[Configuration 3]

In the ignition apparatus according to Configuration 1 or 2, a microwaveradiation antenna serving as the microwave radiation means and anignition/discharge unit serving as the ignition means may be furtherprovided, wherein the microwave radiation antenna and theignition/discharge unit are provided in an integrally formed insulator.

[Configuration 4]

In the ignition apparatus according to any one of Configurations 1 to 3,the microwave radiated from the microwave radiation means may be one ormore controlled intermittent wave.

An internal-combustion engine according to the present inventionincludes any one of the following configurations.

[Configuration 5]

According to an aspect of the invention, there is provided aninternal-combustion engine including a combustion/reaction chamberincluding a cylinder and a piston where mixture of reactive gas andoxidation gas is provided and combustion/reaction or plasma reaction ofthe mixture are carried out; and microwave radiation means for radiatingmicrowave into the combustion/reaction chamber so as to increasetemperature of the mixture in the combustion/reaction chamber and formaking plasma discharge in the combustion/reaction chamber so as toincrease radical concentration, so that characteristics of flameignition is improved and flame propagation speed is promoted, wherein aconcave unit for preventing leakage of the microwave is formed on anouter peripheral surface of the piston coming in contact with an innerwall of the cylinder.

[Configuration 6]

According to another aspect of the invention, there is provided aninternal-combustion engine including a combustion/reaction chamberincluding a cylinder and a piston where mixture of reactive gas andoxidation gas is provided and combustion/reaction or plasma reaction ofthe mixture are carried out; a valve for opening and closing an inletport and an outlet port provided on the combustion/reaction chamber; andmicrowave radiation means for radiating microwave into thecombustion/reaction chamber so as to increase temperature of the mixturein the combustion/reaction chamber and for making plasma discharge inthe combustion/reaction chamber so as to increase radical concentration,so that characteristics of flame ignition is improved and flamepropagation speed is promoted, wherein an architecture for focusing themicrowave on one or more bottom surfaces of the valve is formed on asurface of the valve facing the combustion/reaction chamber.

[Configuration 7]

According to still another aspect of the invention, there is provided aninternal-combustion engine including a combustion/reaction chamberincluding a cylinder and a piston where mixture of reactive gas andoxidation gas is provided and combustion/reaction or plasma reaction ofthe mixture are carried out; ignition means for igniting the mixture inthe combustion/reaction chamber by making discharge; and a magnetinstalled on a circumference of the ignition means or that of thecylinder, wherein a magnetic field generated from the magnet allows anelectric field of ion or plasma generated in the combustion/reactionchamber to have a direction of the piston so that the ion or the plasmaof burned/reacted gas in a flame/reaction zone or in a post stage of theflame/reaction zone is accelerated to an outer peripheral side of thecylinder.

In the internal-combustion engine, characteristics of the ignition byusing the plasma generated by the microwave in flame surface and itspost stage and acceleration of the flame propagation speed are promoted.

[Configuration 8]

According to still another aspect of the invention, there is provided aninternal-combustion engine including a combustion/reaction chamberincluding a cylinder and a piston where mixture of reactive gas andoxidation gas is provided and combustion/reaction or plasma reaction ofthe mixture are carried out; ignition means for igniting the mixture inthe combustion/reaction chamber by making discharge; and voltageregulation means for regulating voltage supplied to the ignition means,wherein the voltage regulation means controlling voltage supplied to theignition means makes discharge below the ignition energy forunburned/unreacted mixture in the combustion/reaction chamber to induceplasma in the mixture and/or discharge for burned/reacted mixture toinduce plasma in the mixture.

In the internal-combustion engine, it is possible to generate the plasmain both before and after the ignition by applying the conventional sparkplug without using the microwave. That is, in the internal-combustionengine, when voltage supplied to the ignition means is the intermittentwave and its amplitude and time length are controlled, it is possible toachieve generation of stable flame and acceleration of the flamepropagation speed under a variety of conditions of load, mixtureconcentration, revolution speed, ignition timing and the like.

[Configuration 9]

According to still another aspect of the invention, there is provided aninternal-combustion engine including a combustion/reaction chamberincluding a cylinder and a piston where mixture of reactive gas andoxidation gas is provided and combustion/reaction or plasma reaction ofthe mixture are carried out; autoignition means for automaticallyigniting the mixture by injecting the mixture of the reactive gas andthe oxidation gas under high pressure to compress the mixture of thereactive gas and the oxidation gas and increase temperature; microwaveradiation means for radiating the microwave into the combustion/reactionchamber; and control means for controlling the autoignition means andthe microwave radiation means, wherein the microwave radiation means andthe ignition means are controlled by the control means so as to repeat acycle that is a process by which the microwave radiation means radiatesthe microwave into the combustion/reaction chamber so that a greatamount of hydroxyl (OH) radical and ozone (O₃) are generated frommoisture of the mixture in the combustion/reaction chamber and thenoxidizes and reacts chemically; and the autoignition means ignites themixture, so that the combustion of the mixture in thecombustion/reaction chamber is promoted by the great amount of hydroxyl(OH) radical and ozone (O₃).

[Configuration 10]

In the internal-combustion engine according to Configuration 5 or 9,measurement sensors for measuring densities of O₂, NO_(x), CO, and sootof gas exhausted from the combustion/reaction chamber may be furtherprovided, to the combustion/reaction or the plasma reaction of themixture of the reactive gas and the oxidation gas is carried out in thecombustion/reaction chamber. As a result, it is possible to carry out acombustion control in a manner that the combustion state is measured inreal time so as to reduce the exhaust gas.

An ignition plug according to the present invention includes thefollowing configuration.

[Configuration 11]

According to an aspect of the invention, there is provided an ignitionplug including a microwave radiation antenna for radiating microwaveinto a combustion/reaction field where combustion/reaction of mixture iscarried out, the mixture of reactive gas and oxidation gas existing in aheat engine or a plasma equipment; and an ignition/discharge unit forigniting the mixture in the combustion/reaction field, wherein themicrowave radiation antenna and the ignition/discharge unit are providedin an integrally formed insulator.

A plasma equipment according to the present invention includes thefollowing configuration.

[Configuration 12]

According to an aspect of the invention, there is provided a plasmaequipment including a microwave oscillator for generating apredetermined microwave band; a microwave resonant cavity for allowingthe predetermined microwave band to resonate; and microwave radiationmeans for radiating the microwave into the microwave resonant cavity,wherein the microwave radiation means is a microwave radiation antennahaving the shape and the size so as to form a strong electric field ofthe microwave in a plasma generation field formed by the microwave.

[Configuration 13]

In the plasma equipment according to Configuration 12, plasma ignitionmeans that makes partial discharge in gas in the microwave resonantcavity and then induces plasma in the gas may be further provided.

[Configuration 14]

In the plasma equipment according to Configuration 13, control means forcontrolling the microwave radiation means and the plasma ignition meansand a measurement unit for measuring the generation amount or emissionintensity of OH radicals and O₃ generated by plasma generation may befurther provided, wherein the microwave radiation means and/or theplasma ignition means process the result of the measurement unit in realtime so as to provide the resultant to the control means.

[Configuration 15]

In the plasma equipment according to Configuration 13 or 14, themicrowave radiation means may include an ignition/discharge unit servingas the microwave radiation means and the plasma ignition means, and themicrowave radiation means and the ignition/discharge unit may beprovided in an integrally formed insulator.

[Configuration 16]

In the plasma equipment according to any one of Configurations 12 to 15,a magnetron for home electric appliances having an oscillation frequencyof 2.45 GHz may be used as the microwave oscillator.

[Configuration 17]

In the plasma equipment according to any one of Configurations 13 to 15,the plasma ignition means may use barrier discharge which inserts aninsulating material such as a dielectric body between electrodes, coronadischarge which forms a non-uniform electric field, and pulse dischargewhich applies less than 1 μs of short pulse voltage.

[Configuration 18]

In the plasma equipment according to Configurations 12, 13, 15, or 16,microwave transmission means may be further provided.

[Configuration 19]

In the plasma equipment according to Configuration 18, the microwavetransmission means may be a coaxial cable.

[Configuration 20]

In the plasma equipment according to Configuration 18, the microwavetransmission means may be a waveguide.

[Configuration 21]

In the plasma equipment according to any one of Configurations 15 to 17,a coaxial cable for transmitting the microwave; a directional couplerfor branching, isolating, and coupling the microwave; and a regulatorfor regulating impedance of entire transmission systems may be furtherprovided.

An exhaust gas degradation apparatus according to the present inventionincludes the following configuration.

[Configuration 22]

According to an aspect of the invention, there is provided an exhaustgas degradation apparatus including a microwave oscillator forgenerating a predetermined microwave band; a microwave resonant cavityfor allowing the predetermined microwave band to resonate; and microwaveradiation means for radiating the microwave into the microwave resonantcavity, wherein the microwave radiation means is a microwave radiationantenna that is disposed on an outer circumference of a flow passage forexhaust gas in circumferential direction of the exhaust gas and that hasthe shape and the size so as to allow a plasma generation field formedby the microwave to uniformly form a strong electric field of themicrowave on a section of the flow passage.

[Configuration 23]

In the exhaust gas degradation apparatus according to Configuration 22,a hollow or solid-core metallic bar or plate for forming the strongelectric field of the microwave along a central axis of the flow passagein which the exhaust gas flows may be further provided.

[Configuration 24]

In the exhaust gas degradation apparatus according to Configuration 22or 23, plasma ignition means that makes partial discharge in gas in themicrowave resonant cavity and then induces plasma in the gas may befurther provided.

[Configuration 25]

In the exhaust gas degradation apparatus according to Configuration 24,the plasma ignition means may be carried out by arc discharge betweenelectrodes disposed in a circumferential direction of the flow passagein which the exhaust gas flows and opposed to each other in an axisdirection.

[Configuration 26]

In the exhaust gas degradation apparatus according to any one ofConfigurations 22 to 25, microwave transmission means may be furtherprovided.

[Configuration 27]

In the exhaust gas degradation apparatus according to Configuration 26,the microwave transmission means may be a coaxial cable.

[Configuration 28]

In the exhaust gas degradation apparatus according to Configuration 26,the microwave transmission means may be a waveguide.

An ozone generating/sterilizing/disinfecting apparatus according to thepresent invention includes the following configuration.

[Configuration 29]

According to an aspect of the present invention, there is provided anozone generating/sterilizing/disinfecting apparatus including amicrowave oscillator for generating a predetermined microwave band to anozone generation field; a microwave resonant cavity disposed on theozone generation field for allowing the predetermined microwave band toresonate; and microwave radiation means for radiating the microwave intothe microwave resonant cavity, wherein the microwave radiation means isa microwave radiation antenna having the shape and the size so as toform a strong electric field of the microwave in the ozone generationfield formed by the microwave.

[Configuration 30]

In the ozone generating/sterilizing/disinfecting apparatus according toConfiguration 29, plasma ignition means that makes partial discharge ingas in the microwave resonant cavity and then induces plasma in the gasmay be further provided, wherein the microwave radiation means is themicrowave radiation antenna having the shape and the size so as to formthe strong electric field of the microwave in the ozone generation fieldformed by the plasma ignition means.

[Configuration 31]

In the ozone generating/sterilizing/disinfecting apparatus according toConfiguration 29 or 30, the gas in the microwave resonant cavity may beair which is at the atmospheric pressure or more.

[Configuration 32]

In the ozone generating/sterilizing/disinfecting apparatus according toConfiguration 29 or 30, the gas in the microwave resonant cavity may besteam which is at the atmospheric pressure or more.

An odor eliminating apparatus according to the present inventionincludes the following configuration.

[Configuration 33]

According to an aspect of the invention, there is provided an odoreliminating apparatus including a microwave oscillator for generating apredetermined microwave band; a microwave resonant cavity for allowingthe predetermined microwave band to resonate; and microwave radiationmeans for radiating the microwave into the microwave resonant cavity,wherein the microwave radiation means is a microwave radiation antennahaving the shape and the size so as to form a strong electric field ofthe microwave in an odor elimination space in the microwave resonantcavity formed by the microwave.

[Configuration 34]

In the odor eliminating apparatus according to Configuration 33, acirculation unit and a circulation system for circulating odorelimination gas and liquid in the microwave resonant cavity may befurther provided.

In an ignition apparatus having Configuration 1, dielectric constantcontrol means controls dielectric constant of mixture in acombustion/reaction field so as to allow resonance frequency of themixture in the combustion/reaction field to resonate with frequency ofthe microwave radiated from microwave radiation means. As a result, itis possible to efficiently increase temperature of the mixture when themicrowave is radiated from the microwave radiation means.

In the ignition apparatus having Configuration 2, the microwaveradiation means radiates the microwave into the combustion/reactionfield to increase the temperature of the mixture in thecombustion/reaction field, and then performs plasma discharge in thecombustion/reaction field to increase radical concentration, so thatcharacteristics of the flame ignition and flame propagation speed arepromoted; ignition means ignites the mixture; and then the microwaveradiation means radiates the microwave into the combustion/reactionfield to promote the combustion/reaction of the mixture. As a result, itis possible to perform the stable and highly efficientcombustion/reaction even when fuel ratio of mixture is decreased andcombustion/reaction of the lean mixture or the non-uniform mixture isperformed.

In the ignition apparatus having Configuration 3, a microwave radiationantenna serving as the microwave radiation means and anignition/discharge unit serving as the ignition means are provided in anintegrally formed insulator. As a result, a microwave radiation antennaand an ignition/discharge unit are compatible with a conventional sparkplug.

In the ignition apparatus having Configuration 4, the microwave radiatedfrom the microwave radiation means is one or more controlledintermittent wave. As a result, it is possible to perform discharge inmultipoint. In addition, it is possible to momentarily generate plasmausing the microwave without increasing power consumption.

In an internal-combustion engine having Configuration 5, a concaveportion for preventing leakage of the microwave is formed on an outerperipheral surface of the piston coming in contact with an inner wall ofthe cylinder. As a result, it is possible to prevent the leakage of themicrowave even when the above-mentioned ignition apparatus is used.

In an internal-combustion engine having Configuration 6, an architecture(an architecture having a ¼ length of wavelength used as an electriclength) for focusing the microwave on one or more bottom surface of avalve is formed on a surface of the valve facing the combustion/reactionchamber. As a result, it is possible to perform an energy radiation suchas discharge to the combustion/reaction field by resonance of themicrowave supplied to the valve by using the above-mentioned ignitionapparatus.

In an internal-combustion engine having Configuration 7, a magneticfield generated from the magnet allows an electric field of ion orplasma generated in the combustion/reaction chamber to have a directionof the piston so that the ion or the plasma of burned/reacted gas in aflame reaction zone or its post stage is accelerated to an outerperipheral side of the cylinder. As a result, it is possible to promotethe characteristics of the flame ignition and acceleration of the flamepropagation speed by using the plasma generated by the microwave in aflame surface and its post stage.

In an internal-combustion engine having Configuration 8, voltageregulation means controlling voltage supplied to the ignition meansmakes discharge below ignition energy for unburned/unreacted mixture inthe combustion/reaction chamber to induce plasma in the mixture and/ordischarge for burned/reacted mixture to induce plasma in the mixture. Asa result, it is possible to generate the plasma in both before and afterthe ignition by applying the conventional spark plug without using themicrowave.

That is, in the internal-combustion engine, when voltage supplied to theignition means is the intermittent wave and its amplitude and its timelength are controlled, it is possible to achieve generation of stableflame and acceleration of the flame propagation speed under a variety ofconditions of load, mixture concentration, revolution speed, ignitiontiming and the like.

In an internal-combustion engine having Configuration 9, the microwaveis radiated into the combustion/reaction field in advance when themixture is automatically ignited by injecting the mixture of reactivegas and oxidization gas under high pressure to the combustion/reactionfield to compress the mixture and increase temperature. As a result, itis possible to generate low-temperature plasma by using theautoignition. Then, a great amount of OH radical and ozone (O₃) can becontinuously generated from moisture in the mixture by the generation ofthe low-temperature plasma. As a result, it is possible to promotecombustion of the mixture in the combustion/reaction field.

In the internal-combustion engine having Configuration 10, measurementsensors for measuring densities of O₂, NO_(x), CO, and soot of gasexhausted from the combustion/reaction chamber is provided, thecombustion/reaction condition in the combustion/reaction chamber can bemonitored. As a result, it is possible to reflect the resultant to acombustion improvement/control using the microwave.

In an ignition plug having Configuration 11, the microwave radiationantenna and the ignition/discharge unit are provided in an integrallyformed insulator. As a result, it is possible to configure theabove-mentioned ignition apparatus using the ignition plug compatiblewith plasma sources such as a conventional spark plug, a glow plug andthe like.

In a plasma equipment having Configuration 12, a microwave oscillatorfor generating a predetermined microwave band; a microwave resonantcavity (cavity) for allowing the microwave of the predetermined band toresonate; and microwave radiation means (microwave radiation antenna)for radiating the microwave into the cavity are provided. As a result,it is possible to efficiently generate the low-temperature plasma byproviding with a microwave radiation antenna having the shape and thesize so as to form a strong electric field of the microwave in a plasmageneration field.

In the plasma equipment having Configuration 13, plasma ignition meansthat makes partial discharge in gas in the cavity and then inducesplasma in the gas is provided. As a result, it is possible toefficiently generate the low-temperature plasma by providing with amicrowave radiation antenna having the shape and the size so as to forma strong electric field of the microwave in a plasma generation field.

In the plasma equipment having Configuration 14, control means forcontrolling the microwave radiation means and the plasma ignition means,and a measurement unit for measuring generation amount or emissionintensity of OH radicals and O₃ generated by plasma generation areprovided. As a result, it is possible to electrically control thegeneration amount of OH radicals and O₃ by processing result of themeasurement unit in real time so as to provide the resultant for thecontrol of the microwave radiation means and/or the plasma ignitionmeans.

In the plasma equipment having Configuration 15, the microwave radiationantenna and the ignition/discharge unit are provided in the integrallyformed insulator. As a result, it is possible to provide the plasmaequipment that is low in cost and compact in size, easily handled andhighly flexible.

In the plasma equipment having Configuration 16, a magnetron for homeelectric appliances in which an oscillation frequency is 2.45 GHz isused. As a result, it is possible to provide the plasma equipment thatis low in cost, readily obtainable, easily repaired/exchanged, and freeof legal regulations in use.

In the plasma equipment having Configuration 17, the plasma ignitionmeans can obtain the same effect when any one of barrier discharge whichinserts an insulating material such as a dielectric body betweenelectrodes, corona discharge which forms a non-uniform electric field,or pulse discharge which applies less than 1 μs of short pulse voltageis used. As a result, it is possible to provide the plasma equipmentthat is flexible regardless of an application condition.

In the plasma equipment having Configuration 18, microwave transmissionmeans is provided. As a result, it is possible to give installationflexibility of a generator while maintaining the same effect.

In the plasma equipment having Configuration 19, a flexible coaxialcable is used for the microwave transmission means. As a result, thereare no limitations for installation of the microwave oscillator whilemaintaining the same effect, so it is possible to provide the flexibleplasma equipment.

In the plasma equipment having Configuration 20, the microwavetransmission means is a waveguide. As a result, it is possible toperform more efficient transmission than the coaxial cable.

In the plasma equipment having Configuration 21, a coaxial cable fortransmitting the microwave; a directional coupler for branching,isolating, and coupling the microwave; and a regulator (stub) forregulating impedance of entire transmission systems are provided. As aresult, it is possible to optimally perform the regulation in a statewhere the transmission efficiency of the microwave of the transmissionsystems is increased. In addition, the microwave oscillator and a plasmageneration position can be separated from each other. As a result, it ispossible to provide more margin for the system design according toapplication position.

In an exhaust gas degradation apparatus having Configuration 22, themicrowave oscillator for generating a predetermined microwave band; themicrowave resonant cavity (cavity) for allowing the microwave of thepredetermined band to resonate; and the microwave radiation means(microwave radiation antenna) for radiating the microwave into thecavity are provided, and the microwave radiation means is disposed onthe outer circumference of a flow passage for exhaust gas in thecircumferential direction of the exhaust gas and has the shape and thesize so as to allow a plasma generation field formed by the microwave touniformly form a strong electric field of the microwave on a section ofthe flow passage. As a result, it is possible to process high-flowexhaust gas.

In the exhaust gas degradation apparatus having Configuration 23, ahollow or solid-core metallic bar or plate for forming a strong electricfield of the microwave along a central axis of the flow passage (flow)in which the exhaust gas flows is provided. As a result, it is possibleto generate the low-temperature plasma that is uniform and strongthroughout a section of the flow passage in which the exhaust gas flowsand along the flow direction.

In the exhaust gas degradation apparatus having Configuration 24, theplasma ignition means that makes partial discharge in gas in the cavityand then induce plasma in the gas is provided. As a result, it ispossible to effectively perform degradation of the exhaust gas byenergy-efficiently generating the plasma by the microwave in the cavity.

In the exhaust gas degradation apparatus having Configuration 25, theplasma ignition means is carried out by arc discharge between electrodesdisposed in a circumferential direction of the flow passage in which theexhaust gas flows and opposed to each other in an axis direction (flow).As a result, it is possible to generate the plasma that is uniform inthe section of the flow passage in an arbitrary section of the axisdirection.

In the exhaust gas degradation apparatus having Configuration 26, themicrowave transmission means is provided. As a result, it is possible tofix the plasma equipment on the online irrespective of the installationposition of the microwave oscillator, eliminating installationlimitation.

In the exhaust gas degradation apparatus having Configuration 27, themicrowave transmission means is a coaxial cable. As a result, it ispossible to fix the plasma equipment on the online irrespective of theinstallation position of the microwave oscillator, eliminating the needof a transmission space in a midstream and structural limitation forinstallation.

In the exhaust gas degradation apparatus having Configuration 28, themicrowave transmission means is a waveguide. As a result, it is possibleto perform a highly efficient transmission more than the coaxial cable.

In an ozone generating/sterilizing/disinfecting apparatus havingConfiguration 29, a microwave oscillator for generating a predeterminedmicrowave band to an ozone generation field; a microwave resonant cavity(cavity) disposed on the ozone generation field for allowing themicrowave of the predetermined band to resonate; and the microwaveradiation means (microwave radiation antenna) for radiating themicrowave into the cavity are provided, and the microwave radiationantenna has the shape and the size so as to form a strong electric fieldof the microwave in the ozone generation field. As a result, it ispossible to generate high flow ozone.

In the ozone generating/sterilizing/disinfecting apparatus havingconfiguration 30, the plasma ignition means that makes partial dischargein gas in the cavity and then induces plasma in the gas is provided, andthe microwave radiation antenna has the shape and the size, which formsthe strong electric field of the microwave in the ozone generation fieldformed by the plasma ignition means. As a result, it is possible toeffectively generate high flow ozone by energy-efficiently generatingthe plasma by the microwave in the cavity.

In the ozone generating/sterilizing/disinfecting apparatus havingConfiguration 31, the gas in the cavity is air that is at theatmospheric pressure or more. As a result, it is possible to easilyperform generation in a large amount at a low cost without any specialstructure.

In the ozone generating/sterilizing/disinfecting apparatus havingConfiguration 32, the gas in the cavity is steam which is at theatmospheric pressure or more is used. As a result, it is also possibleto perform generation in a large amount at a low-cost and easy withoutany special structure.

In an odor eliminating apparatus having Configuration 33, a microwaveoscillator for generating a predetermined microwave band; a microwaveresonant cavity (cavity) for allowing the microwave of the predeterminedband to resonate; and microwave radiation means (microwave radiationantenna) for radiating the microwave into the cavity are provided, andthe microwave radiation antenna has the shape and the size so as to forma strong electric field of the microwave in an odor elimination space inthe cavity formed by the microwave. As a result, it is possible toimprove an odor elimination effect by generating a great amount ofozone.

In the odor eliminating apparatus having Configuration 34, a circulationunit and a circulation system for circulating an odor elimination gasand liquid are provided in the cavity. As a result, it is possible toprovide the odor eliminating apparatus in which the odor eliminationeffect is further improved.

That is, the present invention provides an ignition apparatus capable ofattaining stabilization of ignition, improvement of combustion speed,promotion of combustion of non-uniform mixture, and improvement of fuelconsumption rate by performing the stable and highly efficientcombustion/reaction even when fuel ratio of mixture is decreased andcombustion/reaction of the lean mixture is performed in a heat enginesuch as a reciprocating engine, a rotary engine, a jet engine and a gasturbine, or a plasma equipment.

In addition, the present invention provides the internal-combustionengine to which the ignition apparatus according to the presentinvention is suitably applied. Further, the present invention providesthe ignition plug suitably applied to the ignition apparatus accordingto the present invention. The ignition plug can be used as the ignitionapparatus in the internal-combustion engine as well as acombustion/reaction device. Accordingly, it is possible to contribute tostabilization of the flame, improvement of fuel consumption, andimprovement of combustion/reaction efficiency.

Furthermore, the present invention provides an inexpensive and compactapparatus that induces plasma easily at the atmospheric pressure andgenerates a great amount of OH radicals and O₃. The apparatus may beapplied to a process device for decreasing and reducing hazardouseffluents (CO₂, NO_(x), and unburned hydrocarbon), volatile organiccompound (VOC), suspended particulate matter (PM), soot, and the like.In addition, the apparatus may be applied to a plasma equipment, anexhaust gas degradation apparatus, a hazardous material processapparatus, an ozone generating/sterilizing/disinfecting apparatus, andan odor eliminating apparatus used in an environmental (an in-plant andan end-of-pipe) countermeasure field such as application to an electricdust collector and process and reuse of tar, sludge, and drainage, and amedical/hygiene field such as sterilization, pasteurization, andcleaning technologies.

In addition, the apparatus can be applied to not only the end-of-pipecountermeasure technology but the in-plant countermeasure technology. Itis possible to provide the suitable plasma equipment capable ofperforming stable and highly efficient combustion in various combustorssuch as a gas turbine, a furnace, an incinerator, and a pyrolyticfurnace so that a combustion process is improved (energy saving byextension of the combustion limit of lean fuel) and the hazardouseffluents are decreased and reduced by decomposing and completelyburning of unburned fuel without reducing output of power.

It is possible to provide the ozone generating/sterilizing/disinfectingapparatus and the odor eliminating apparatus easily generating a greatamount of O₃ at a low cost, in a high-efficiently and energy savingmanner.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a graph showing correlation between temperature and dielectricconstant of mixture in an internal-combustion engine to which anignition apparatus according to the present invention is applied.

FIG. 2 is a graph showing pulse width of microwave in the ignitionapparatus according to the present invention.

FIG. 3 is a side view showing a configuration of a combustion/reactionchamber in the internal-combustion engine.

FIG. 4 is a graph showing pulse width and output of the microwave of afour-stage multipoint ignition according to the present invention.

FIG. 5 are sectional views showing a configuration of an ignition plugaccording to the present invention.

FIG. 6 is a side view showing the configuration of the ignition plugaccording to the present invention.

FIG. 7 are a side view and top plan views showing a configuration of amain part of an internal-combustion engine according to a firstembodiment of the present invention.

FIG. 8 are sectional views showing a configuration of a main part of aninternal-combustion engine according to a second embodiment of thepresent invention.

FIG. 9 are side views showing another example of a configuration of aninternal-combustion engine according to the present invention.

FIG. 10 are sectional views showing another example of a configurationof an internal-combustion engine according to the present invention.

FIG. 11 is a side view showing a configuration of a main part of aplasma equipment according to a first embodiment of the presentinvention.

FIG. 12 is a side view showing a configuration of a main part of aplasma equipment according to a second embodiment of the presentinvention. In addition, FIG. 12 is a side view showing a configurationof a main part of an exhaust gas degradation apparatus according to afirst embodiment of the present invention.

FIG. 13 is a side view showing a configuration of a main part of aplasma equipment according to a third embodiment of the presentinvention.

FIG. 14 is a side view showing a configuration of a main part of aplasma equipment according to a fourth embodiment of the presentinvention. In addition, FIG. 14 is a side view showing a configurationof a main part of an exhaust gas degradation apparatus according to asecond embodiment of the present invention.

DESCRIPTION OF REFERENCE NUMERALS AND SIGNS

-   1: Microwave Radiation Antenna-   2: Ignition/Discharge Unit-   3: Coaxial Cable-   4: Ground Terminal-   5: Anode Terminal-   6: Cylinder-   7: Piston-   8: Combustion/Reaction Chamber-   9: Concave Portion-   10: Inlet Port-   11: Outlet Port-   12: Valve-   13: Periodic Architecture-   14: Shaft-   15: Magnet-   16: Insulating Material-   17: Microwave Oscillator-   18: Microwave Resonant Cavity (Cavity)-   19: Microwave Radiation Means (Microwave Radiation Antenna)-   20: Plasma Ignition Means-   21: Plasma Generation Field-   22: Fluid in Cavity-   23: Measurement Unit-   24: Control Means-   25: Coaxial Cable

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the invention will be described withreference to the drawings.

[First Embodiment of Ignition Apparatus]

In a heat engine or a plasma equipment, mixture of reactive gas andoxidation gas is provided. In a combustion/reaction field in which acombustion/reaction of the mixture is caused, for example, acombustion/reaction chamber of an engine, when temperature of themixture is increased or ignition is carried out by microwave, it isnecessary to efficiently transmit required energy to thecombustion/reaction chamber for the purpose of the temperature increaseor the ignition. For this reason, it is preferable that resonancefrequency determined by the shape of the combustion/reaction chamber,dielectric constant (∈) of the mixture and the like corresponds tofrequency of the microwave. On the other hand, as a magnetron used forgenerating the microwave, a number of the magnetrons which have aoscillating frequency of 2.45 GHz and allow water molecules to resonateare already manufactured and used for home electric appliances. Inaddition, as for a magnetron used for a fish detector and a radar, themagnetrons which have much higher frequency are commercially used.

If the resonance frequency of the combustion/reaction chamber can becorresponded with the frequency of 2.45 GHz for example, it is possibleto use the magnetrons of 2.45 GHz distributed in large quantities andlow in price. This is desirable as it permits easy and low-costmanufacturing of an apparatus.

However, since the shape of the combustion/reaction chamber depends onan inner shape of a cylinder and a shape of a piston that are determinedby various factors other than the resonance frequency, it is difficultto make a shape that allows the resonance frequency fixed in allengines.

Thus, in an ignition apparatus according to the present invention, thedielectric constant (∈) of the mixture is controlled by introducingwater and/or exhaust gas into the combustion/reaction chamber so thatthe resonance frequency of the mixture in the combustion/reactionchamber corresponds to the microwave frequency.

That is, the ignition apparatus includes a dielectric constant controlmeans. The dielectric constant control means controls the dielectricconstant of the mixture in a combustion/reaction field by introducingwater and/or the exhaust gas which is exhausted from thecombustion/reaction field into the combustion/reaction field (thecombustion/reaction chamber or the like) in which combustion/reaction ofthe mixture of reactive gas and oxidation gas that exist in a heatengine or a plasma equipment is carried out.

Variation in the dielectric constant (∈) of the mixture in thecombustion/reaction chamber depends on variation in air-fuel ratio (A/Fvalue) by change of amount of gasoline which is injected into thecombustion/reaction chamber. As shown in FIG. 1, the variation of thedielectric constant (∈) can also be caused by introducing water (steam)into the combustion/reaction chamber independent of the mixture. Thus,the dielectric constant of the mixture in the combustion/reactionchamber can be controlled by the dielectric constant control means byintroducing water into the combustion/reaction chamber. A process ofintroducing water into the combustion/reaction chamber may be carriedout in the manner that water stored in a tank is sent into thecombustion/reaction chamber by a pump, for example.

In addition, a process of reintroducing the exhaust gas which isexhausted from the combustion/reaction chamber into thecombustion/reaction chamber is called “EGR” (exhaust gas returning).Since the “EGR” is conventionally carried out, the known mechanism canbe used as a specific mechanism for reintroducing the exhaust gas intothe combustion/reaction chamber.

The dielectric constant control means controls an amount of steam ortemperature in the combustion/reaction chamber by introducing waterand/or the exhaust gas into the combustion/reaction chamber, so that thedielectric constant (∈) of the mixture is controlled. In addition, thedielectric constant control means controls the resonance frequency ofthe mixture in the combustion/reaction chamber to correspond to themicrowave frequency that is radiated by a microwave radiation meansdescribed below.

The ignition apparatus includes the microwave radiation means forradiating the microwave into the combustion/reaction field so as toincrease temperature of the mixture in the combustion/reaction field. Ageneral magnetron which has an oscillation frequency of 2.45 GHz can beused as the microwave radiation means. The magnetron which has theoscillation frequency of 2.45 GHz is used in a so-called microwave ovenand then manufactured and distributed in large quantities. On the otherhand, the microwave radiation means is not limited to the magnetron, buta transmitter or the like of a high-frequency band used in a mobilephone or the like can also be used. In this case, it is possible toprovide an apparatus that is smaller and portable. In addition, it ispreferable that the microwave radiation means radiates the microwave asmicrosecond pulse or one or more of intermittent radiation. When themicrowave is intermittently radiated, it is possible to generate plasmausing the microwave having momentary high power without increasing powerconsumption.

Further, the oscillation form of the microwave can be controlled byconfiguring an optimal combination of pulse, intermittent radiation andcontinuous radiation for an object to which the present invention isapplied.

In addition, continuous duration (pulse width) of the intermittentmicrowave can be optimized by the heat engine or the plasma equipmentrespectively. For example, as shown in FIG. 2, when a mechanism of themicrowave oven with an inverter is used, it is possible to radiate themicrowave with a pulse width of 3 μsec to 18 μsec at the period of about16 msec. Further, the amplitude and the period of intermittent microwavecan be arbitrarily set.

In such an ignition apparatus, the microwave generated by the microwaveradiation means is configured to be transmitted into thecombustion/reaction chamber via a coaxial cable.

In addition, the ignition apparatus includes ignition means for ignitingto the mixture in the combustion/reaction chamber. The ignition meansthat includes an ignition/discharge unit such as a spark plug that isgenerally used in a gasoline engine or a glow plug that is generallyused in a diesel engine can be used.

In the ignition apparatus, as the ignition means, the microwaveradiation means may be also used as the ignition means without using thespark plug or the glow plug. In addition, as the ignition means foreasily generating a plasma by microwave, electrons may be thermallysupplied thereto by means such as laser beam, flame of a lighter or aburner and the like, a heater and a metallic piece of high temperature.

In the ignition apparatus, the dielectric constant control meanscontrols the dielectric constant (∈) of the mixture before thecombustion/reaction of the mixture in the combustion/reaction chamber iscarried out so that the resonance frequency of the mixture in thecombustion/reaction chamber corresponds to the frequency of themicrowave radiated by the microwave radiation means. In this state, whenthe microwave is radiated by the microwave radiation means, the entirecombustion/reaction chamber resonates, and thus temperature of themixture in the combustion/reaction chamber is efficiently increased sothat the ignition easily occurs.

When the temperature of the mixture in the combustion/reaction chamberis increased, the ignition means carries out the ignition, and thus thecombustion/reaction is satisfactorily caused in the mixture. In theignition, so-called volumetric ignition, point ignition in a localregion, or multistage ignition may be carried out by the use ofresonance by the microwave. That is, the ignition apparatus is a systemcapable of generating plasma by using the microwave before the ignition,at the ignition time, and after the ignition.

In addition, ignition delay should be taken into consideration for theignition timing. So it is preferable that the ignition is carried out atthe predetermined time before the time when the piston reaches top deadcenter and the volume of the combustion/reaction chamber is therebymaximally compressed. Fuel concentration (air-fuel ratio) and ignitiontiming can be optimized by the heat engine or the plasma equipmentrespectively, thereby acquiring the maximum output of power.

In the ignition apparatus, the dielectric constant of the mixture can beaccurately controlled by optimizing the amounts of water, recirculatedexhaust gas, fuel, and the like introduced into the combustion/reactionchamber. Additionally, the optimization may be adequately determined inconsideration of oxygen concentration, temperature of the mixture,residual gas concentration, and the like in the combustion/reactionchamber.

Accordingly, comparing with a conventional ignition apparatus used in aheat engine or a plasma equipment, the ignition apparatus can performstable combustion/reaction even when fuel ratio in the mixture is lowand mixture concentration is nonuniform.

Further, the ignition apparatus can be applied to a jet engine and thelike that have no closed combustion/reaction chamber as acombustion/reaction field. In the jet engine and the like, intake,mixture, combustion/reaction and exhaust are sequentially carried out incontinuous spaces of the engine. However, as described above, theignition apparatus controls the dielectric constant of the mixture,radiates the microwave and performs ignition continuously orintermittently in the field in which the combustion/reaction operationis carried out.

Furthermore, in the ignition apparatus, the microwave radiation means isnot limited to the magnetron having a oscillation frequency of 2.45 GHz,but may use a magnetron oscillating at resonance frequency of thehydrocarbon molecule, the carbon molecule, the hydrogen molecule, or thelike in fuel. In this case, it is not necessary to introduce water intothe combustion/reaction field.

[Second Embodiment of Ignition Apparatus]

The ignition apparatus according to the second embodiment includes themicrowave radiation means and the ignition means in the same manner asthe ignition apparatus according to the above-mentioned firstembodiment. Further, the ignition apparatus includes control means forcontrolling the microwave radiation means and the ignition means.

The control means controls the microwave radiation means and theignition means and performs following cycle repeatedly. The cyclecomprises increasing the temperature of the mixture in thecombustion/reaction chamber 8 or generating radicals by radiating themicrowave into a combustion/reaction chamber 8 by the microwaveradiation means as shown in FIG. 3, then performing the ignition to themixture by the ignition means, next promoting the combustion/reaction ofthe mixture in the combustion/reaction chamber by radiating themicrowave into the combustion/reaction chamber by the microwaveradiation means.

That is, in this ignition apparatus, generation timing and output ofpower (input energy) of the microwave are controlled, thereby realizinga combustion/reaction cycle of temperature increase, radical generation,ignition and promotion of flame propagation in the mixture. At thistime, water and/or exhaust gas may be introduced into the mixture beforethe combustion/reaction in the same manner as the above-mentioned firstembodiment.

Further, in this ignition apparatus, for example, four-stage multipointignition can be carried out. In a first stage, the microwave is radiatedto the mixture before the ignition so as to increase the temperature ofwater in the mixture. In a second stage, the microwave is radiated tothe mixture before the ignition so as to generate plasma discharge inthe combustion/reaction field, thereby increasing radical concentration.In the first and second stages, the ignition characteristics of themixture are enhanced, thereby enabling the ignition to easily occur. Ina third stage, ignition is carried out by discharging in the mixture inthe combustion/reaction field. At this time, the ignition may be carriedout by using a conventional spark plug. In a fourth stage, the microwaveis radiated to the mixture after the ignition so as to generate theplasma discharge in the combustion/reaction field, thereby increasingthe radical concentration, or the microwave is radiated so as togenerate a stationary wave by using the microwave, thereby promoting theflame propagation.

In addition, as shown in FIG. 4, the pulse width and the output of power(input energy) of the microwave in the four-stage multipoint ignitioncan be configured to acquire the maximum output by optimizing the outputand the pulse width of the microwave for each step in the heat enginesor the plasma equipments. Further, temperature increase of the mixture,generation of radicals such as OH radicals, the ignition and thepromotion of the flame propagation can be carried out by the microwaveradiation by controlling the output of the microwave and amplitude andperiod of the intermittent wave.

In this ignition apparatus, the combustion/reaction operation ispromoted as described above so that lean mixture that is not possible toperform combustion/reaction by a conventional ignition apparatus is nowefficiently combusted/reacted, thereby improving fuel/reactantconsumption rate, decreasing size of the combustion/reaction chamber,improving output, and cleaning the exhaust gas in a stable output state.Further, in this ignition apparatus, since imperfect combustion/reactionis prevented and complete combustion/reaction is realized, it ispossible to suppress occurrences of air contaminants, therebycontributing to an environmental conservation.

[Embodiment of Ignition Plug]

As shown in FIG. 5A, an ignition plug according to the present inventionincludes a microwave radiation antenna 1 serving as the microwaveradiation means and an ignition/discharge unit 2 serving as the ignitionmeans. The microwave radiation antenna and the ignition/discharge unitare provided in an integrally formed insulator. The ignition plug iscompatible with a spark plug and a glow plug generally used in theconventional gasoline engine and the conventional diesel engine, therebyconstituting the above-mentioned ignition apparatus according to thepresent invention.

In this ignition plug, the microwave is transmitted from a magnetron(not shown) to the microwave radiation antenna 1 via a coaxial cable 3.Further, this ignition plug includes a cylindrical ground terminal 4surrounding the microwave radiation antenna 1. The ignition/dischargeunit 2 is formed between an end of an anode terminal 5 to which voltageis applied from a power source (not shown) and an end of the cylindricalground terminal 4.

As shown in FIG. 5B, the ignition plug may be configured so that themicrowave radiation antenna 1 is cylindrically shaped to house the anodeterminal 5. In this case, the ground terminal 4 should be bar-shaped anddisposed outside the microwave radiation antenna 1. In this case, theignition/discharge unit 2 is formed between the ends of the anodeterminal 5 and the ground terminal 4.

In the ignition plug, as shown in FIG. 6, the microwave radiationantenna 1 and the ignition/discharge unit 2 are integrally configured soas to be compatible with the conventional and general spark plug.Further, in the ignition plug, the spark (electrical discharge) servingas the ignition means and the microwave radiation serving as themicrowave radiation means are possible, thereby easily configuring theabove-mentioned ignition apparatus. In addition, the ignition plugsshown in FIGS. 5 and 6 have a structure in which the four-stagemultipoint ignition according to the second embodiment of the abovementioned ignition apparatus is possible.

[First Embodiment of Internal-Combustion Engine]

As shown in FIG. 7, an internal-combustion engine according to thepresent invention is constituted by a cylinder 6 and a piston 7. Theinternal-combustion engine includes a combustion/reaction chamber 8provided with mixture of fuel and air and the combustion/reaction of themixture is carried out. In addition, the internal-combustion engineincludes the microwave radiation antenna 1 serving as the ignitionapparatus according to the above-mentioned embodiment. In theinternal-combustion engine, concave portions 9 for preventing leakage ofthe microwave are formed on the outer peripheral surface of piston 7being in sliding contact with the inner wall of the cylinder 6.

The concave portions 9 are intermissive annular grooves surrounding theouter peripheral surface of the columnar piston 7. When the intervalbetween the inner wall of the cylinder 6 and the piston is denoted by D,the wavelength of the microwave is denoted by λ, the widths (groovewidths) L of the concave portions 9 are preferable to be in the rangefrom no fewer than 8 D to nor more than λ/8. In addition, the depths(groove depths) of the concave portions 9 are set to be λ/4.

As shown in FIG. 7A, the concave portions 9 cover about 80% of the wholecircumference (360 degree) of the outer peripheral surface of the piston7, thereby preventing the microwave from leaking from the cylinder 6 inthe case where the wavelength of the microwave is not disturbed.Further, as shown in FIG. 7B, the concave portions 9 allow the microwaveto pass when the wavelength of the microwave is disturbed, and thus themicrowave at a specific frequency is selectively trapped, therebystabilizing the inside of the chamber.

[Second Embodiment of Internal-Combustion Engine]

As shown in FIG. 8, the internal-combustion engine according to thepresent invention includes the cylinder and the piston. Theinternal-combustion engine includes a combustion/reaction chamber 8provided with mixture of fuel and air and the combustion/reaction of themixture is carried out, and valves 12 for opening and closing an inletport 10 and an outlet port 11 provided to the combustion/reactionchamber 8. In addition, the internal-combustion engine includes themicrowave radiation means serving as the ignition apparatus according tothe above-mentioned embodiment. As described above, the microwaveradiation means radiates the microwave into the combustion/reactionchamber 8, thereby at least increasing the temperature of the mixture inthe combustion/reaction chamber 8.

Then, in the internal-combustion engine, periodic architectures 13 (forexample, a rim bone, a vane strap, and a corrugate) are formed on thesurfaces of the valves 12 facing combustion/reaction chamber 8. Theperiodic architectures 13 resonate with the microwave and focus themicrowave for one or more bottom surfaces of the valves 12, that is, forengine combustion chamber side. The periodic architectures 13 areprotrusions made in the same shape as the resonator in the magnetron bynitride and the like. In addition, concave portions between theprotrusions constituting the periodic architectures 13 are filled withan insulating material such as ceramic, and the surfaces of the valves12 facing the combustion/reaction chamber 8 are flatly shaped.

In the internal-combustion engine, the microwave is transmitted from themagnetron to the surfaces of the valves 12 facing thecombustion/reaction chamber 8 via shafts 14 of the valves 12. Then, themicrowave resonates in the periodic architectures 13 of the valves 12,thereby being converted into currents. Accordingly, when the microwaveis transmitted to the periodic architectures 13 of the valves 12, sparksoccur in the periodic architectures 13. That is, in theinternal-combustion engine, ignition of the mixture by sparks can beperformed without using spark plugs. In addition, it is preferable thatthe diameter of the shafts 14 of the valves 12 is 8 mm or less in orderto prevent the leakage of the microwave.

In the internal-combustion engine, since the conventional spark plug isnot necessary to be provided, there becomes more room. Thus, increase insize of the inlet port 10 and the outlet port 11 can be achieved,thereby improving the efficiency of the combustion/reaction. Inaddition, in the internal-combustion engine, the multipoint ignition canbe performed on the substantially entire surface of each valve 12 facingthe combustion/reaction chamber 8, thereby realizing stablecombustion/reaction.

In addition, in the internal-combustion engine, not all of energy of themicrowave is spent for spark. It is possible to adjust the ratio betweenthe energy spent for spark of the microwave and the energy serving asthe microwave radiated into the combustion/reaction chamber 8 byoptimizing the output, the pulse width, and the like of the microwave.Therefore, it is possible to configure the ignition apparatus asdescribed above.

Further, in the internal-combustion engine, as shown in FIG. 9, amagnetic field and an electric field are generated by providing amagnetic 15 in the proximity of the shaft 14 of the valve 12 to whichthe microwave is transmitted. Therefore, it is possible to promote thecombustion/reaction by plasma generation and promoting the flamepropagation.

Furthermore, in the internal-combustion engine, as shown in FIG. 10, itis preferable that the periodic architectures 13 (a protrusion ofnitride and the like having the same shape as the resonator in themagnetron) resonating with the microwave are provided on the inner wallof the combustion/reaction chamber 8 and the microwave is generated inthe periodic architectures 13 by supplying current to the periodicarchitectures 13.

[First Embodiment of Plasma Equipment]

As shown in FIG. 11, a plasma equipment according to the presentinvention includes a microwave oscillator 17, a microwave resonantcavity (cavity) 18 resonating at a predetermined microwave band,microwave radiation means (microwave radiation antenna) 19 for radiatingthe microwave into the cavity, and plasma ignition means 20 forperforming partial electrical discharge to the gas in the cavity toinduce plasma in the gas. The microwave radiation antenna 19 forms astrong electric field of the microwave in a plasma generation field 21by using the plasma ignition means 20.

Thermal nonequilibrium plasma of a high pressure field (atmosphericpressure, or 0.2 MPa or more) is generated in a fluid 22 in themicrowave resonant cavity (cavity) to oxidize, react chemically anddetoxify hazardous effluents, chemical substances, suspended particulatematter, soot and the like by using products materials of plasma (OHradicals and ozone (O₃)). An exceptional merit of the atmosphericthermal nonequilibrium plasma is that the response speed and thematerial conversion ratio can be controlled substantially independentlyof temperature and pressure since the restriction of thermochemicalequilibrium is avoided. Thus, there is high degree of freedom to designa reactor reacted to the generated plasma. Thus, the reactor can beconfigured to be light, compact and highly-responsive. The atmosphericthermal nonequilibrium plasma may be used, for example, for directsynthesis of methanol from methane, steam reforming of natural gas,acetylene composition, natural gas liquefaction and the like.

At this time, the pressure of the generated plasma is set to the linepressure of a process fluid of the detoxified hazardous effluents,chemical substances, suspended particulate matter, soot, and the like.In addition, processed quantity is determined by flow rate of a line.

Incidentally, the inventor has carried out various fundamentalresearches in order to generate the plasma of a high pressure field.Based on the research outcome, it turned that maintenance of stableplasma is possible by igniting a plasma material in some way andsupplying energy thereto. For this reason, the plasma ignition means 4ignites thermal non-equilibrium plasma by using any one of barrierdischarge which inserts an insulating material such as a dielectric bodybetween electrodes, corona discharge which forms a non-uniform electricfield, and a pulse discharge which applies less than 1 μs of short pulsevoltage. For example, the plasma is partially ignited by usingelectrical discharge of a spark plug for a gasoline vehicle or a glowplug. In order to grow the generated plasma, a strong electric field isformed in the plasma generation field 21 in the proximity of anelectrical discharge position of the spark plug or the glow plug byusing the microwave transmitted from a microwave transmitter 1.Accordingly, the energy of the microwave is absorbed into the thermalnonequilibrium plasma, thereby the plasma grows (volumetric ignition).In such a process, OH radicals which allow chemical active reaction tooccur and O₃ having strong oxidizability increase in great numbers byhundreds of times of orders. The reaction is promoted by adding waterwhich is the source of OH radicals and O₃. In addition, in order topromote the reaction, it is effective to apply 1 GHz or more of themicrowave in which water molecules resonate thereto. As a magnetron forgenerating the microwave, it is desirable to use the magnetron which hasbeen already manufactured for home electric appliances (for example, amagnetron for a microwave oven having the oscillating frequency of 2.45GHz) in large quantities all over the world, in view of an apparatusthat is easy and inexpensive to manufacture.

In addition, depending on processed objects such as hazardous substanceand the like, the microwave radiation means is not limited to themagnetron having an oscillation frequency of 2.45 GHz, but may use amagnetron oscillating at resonance frequency of the hydrocarbonmolecule, the carbon molecule, the hydrogen molecule, and the like infuel. In this case, it is not necessary to introduce water into thecombustion field.

[Second Embodiment of Plasma Equipment]

As shown in FIG. 12, the plasma equipment according to the presentinvention includes the microwave oscillator 17, the microwave resonantcavity (cavity) 18 resonating at a predetermined microwave band, themicrowave radiation means 19 (the microwave radiation antenna) forradiating the microwave to the plasma generation field 21 in the cavity,the plasma ignition means 20 for performing partial electrical dischargeto gas 22 in the cavity to induce plasma in the gas, a measurement unit23 for measuring the generation amount or emission intensity of OHradicals and O₃ generated by the plasma generation and a control means24 for controlling input energy/pattern of the microwave radiation meansand the plasma ignition means. Arrows in FIG. 12 indicate a flowingdirection of a fluid 25 that is processed or burned by the plasma.

As described in the first embodiment, an OH sensor and an O₃ sensor ofthe measurement unit 23 provided on the downstream side performsreal-time detection of the generation amount or emission intensity of OHradicals and O₃ of the fluid which is detoxified or oxidized by theplasma generation and chemically reacted by OH radicals. Based on thecalculated detection result, the microwave radiation means 19 and theplasma ignition means 20 are controlled to the predetermined valuesunder a certain control range, thereby controlling the process amount ofthe hazardous substance and the like flowing through the plasmaequipment.

[Third Embodiment of Plasma Equipment]

As shown in FIG. 13, the plasma equipment according to the presentinvention makes smaller and less expensive microwave radiation means 19according to the first embodiment or the second embodiment of thepresent invention. This is realized by fitting the antenna 19 to theconventional spark plugs or the glow plugs. In this case, an end of theantenna 19 is branched so as to surround the ignition/discharge unit,thereby forming a strong electrical field.

[Fourth Embodiment of Plasma Equipment]

As shown in FIG. 14, the plasma equipment according to the presentinvention includes a coaxial cable 26 for transmitting the microwave, adirectional coupler 27 for branching, isolating, and coupling themicrowave, and a regulator (stub) 28 for regulating impedance of entiretransmission systems according to the first to third embodiments of thepresent invention. For example, when the present invention is applied toa vehicle engine, the microwave oscillator 17 is not installed in anengine exposed to intense vibration but at a position where vibrationand temperature do not vary, so that durability and reliability of themicrowave oscillator 17 are improved. In addition, by providing thedirectional coupler, it is possible to realize an apparatus branchingthe energy from the microwave oscillator to multipoint in a combustionchamber or online reactor (a position at which hazardous substance andthe like are detoxified by plasma) to perform uniform process.

[Fifth Embodiment of Plasma Equipment]

As shown in FIG. 13, the plasma equipment according to the presentinvention includes a coaxial cable 26 for transmitting the microwave, adirectional coupler 27 for branching, isolating, and coupling themicrowave, and a regulator (stub) 28 for regulating impedance of entiretransmission systems according to the first to third embodiments of thepresent invention. For example, when the present invention is applied toa vehicle engine, the microwave oscillator 17 is not installed in anengine exposed to intense vibration but at a position where vibrationand temperature do not vary, so that durability and reliability of themicrowave oscillator 17 are improved. In addition, by providing thedirectional coupler, it is possible to realize an apparatus branchingthe energy from the microwave oscillator to multipoint in a combustionchamber or online reactor (a position at which hazardous substance andthe like are detoxified by plasma) to perform uniform process.

[First Embodiment of Exhaust Gas Degradation Apparatus]

A basic configuration of an exhaust gas degradation apparatus accordingto the present invention is the same as that of the plasma equipment inFIG. 12 or 14. As shown in FIG. 12 or 14, the exhaust gas degradationapparatus includes the microwave oscillator 17, the microwave resonantcavity (cavity) 18 resonating at a predetermined microwave band, themicrowave radiation means (microwave radiation antenna) 19 for radiatingthe microwave to the plasma generation field in the cavity, the plasmaignition means 20 for performing partial electrical discharge to the gas22 in the cavity to induce plasma in the gas, the measurement unit 23for measuring the generation amount or emission intensity of OH radicalsand O₃ generated by plasma generation, and the control means 24 forcontrolling an input energy/pattern of the microwave radiation means andthe plasma ignition means. Arrows in a drawing indicate a flowingdirection of an exhaust gas fluid 25 that is processed or burned by theplasma.

As described in the above-mentioned first embodiment, exhaust gases suchas unburned gas, soot, NO_(x) and the like in the combustion/reactionchamber are detoxified into stable and nonhazardous oxide and carbonsuch as NO₂ and CO₂ by breaking and oxidizing carbon-carbon bond andcarbon-hydrogen bond by strong oxidizability of ozone and OH radicalsaccompanied with plasma generation and chemically reacting by OHradicals. The OH sensor and O₃ sensor of the measurement unit 6 providedon the downstream side measures in real time the generation amount oremission intensity of OH radicals and O₃. Based on the calculatedmeasurement result, the microwave radiation means 19 and the plasmaignition means 20 are controlled to the predetermined values under acertain control range, thereby it is possible to control the processamount of the hazardous substance and the like flowing through theplasma equipment.

[Example of Use of Ozone Generating/Sterilizing/Disinfecting Apparatusand Odor Eliminating Apparatus]

For example, when the present invention is applied to a jet engine foran aircraft, the present apparatus is installed in the proximity of ajet engine exhaust cone, and thus high pressure steam containingmoisture can be converted into a great amount of OH radicals and O₃ byusing the thermal nonequilibrium plasma generated in the presentapparatus. The atmosphere has been polluted by exhaust gases ofaircraft, but it is possible to degrade the exhaust gas intononhazardous gas by a great amount of OH radicals and O₃ which havestrong oxidizability. Further, it is possible to generate a great amountof O₃ so as to restore the ozone layer in the stratosphere which hasbeen damaged by CFC and the like.

In addition, it is possible to promote combustion of compressed mixedfuel using strong radical reaction by installing the present apparatusat a combustion chamber located at a rear stage of a jet enginehigh-pressure compressor. Accordingly, it is possible to contribute toenvironmental conservation by discharging clean exhaust gas instead ofexhaust gas polluting the atmosphere. The OH sensor and O₃ sensor of themeasurement unit 6 provided on the downstream side measures in real timethe generation amount or emission intensity of OH radicals and O₃. Basedon the calculated measurement result, the microwave radiation means andthe plasma ignition means are controlled to the predetermined valuesunder a certain control range, thereby it is possible to control theproduction amount of the hazardous substance and the like by controllingcombustion in the combustion chamber.

[Example of Use of Internal-combustion Engine and Plasma EquipmentAccording to the Present Invention]

Even when biogas, very lean methane gas, very low calorie gas and thelike are used as fuel of the internal-combustion engine and the plasmaequipment according to the present invention, chemical reaction can bepromoted by using strong oxidizability of OH radicals and the O₃generated by the plasma generation. Therefore, it is now possible toburn these gases in a normal gas engine without help of additionalgases. Further, it is possible to improve output, electric generationefficiency and the like.

[Example of Use of Plasma Equipment According to the Present Invention]

A great amount of spectral light can be generated from N₂ contained inthe air by using the plasma equipment according to the present inventionin the atmospheric pressure air. When the spectrum is focused and thenderived via fiber and the like, it is possible to provide an inexpensiveand compact N₂ spectral source and a pulse source in place of anexpensive, conventional laser source.

[Example of Use of Ozone Generating/Sterilizing/Disinfecting Apparatusand Odor Eliminating Apparatus According to the Present Invention]

When the apparatus according to the present invention is installed at acorner in a building located in a construction site and then operated ina state where the building is closed, substances causing the sick housesyndrome are removed, various odors of paints, adhesive pastes,antiseptic agents and the like are deodorized, and bacteria, viruses andallergic substances are sterilized and disinfected. In this case, it ispossible to discharge post-processed detoxified air by installing theapparatus according to the present invention at a rear stage of a simpleair exhauster located in a construction site. Alternatively, by fittingthe present apparatus into a cleaner which is a general home electricappliance, it is possible to degrade hazardous substances on a surfaceof cleaned objects by OH radicals and O₃ generated in the presentapparatus during cleaning. Although an architectural structure (communalfacility, building, gym, auditorium, shopping mall, and so forth) isdescribed as an object, it is possible to get the most out of the sameeffect by applying the present invention to sterilization,deodorization, and disinfection of an object which has an arbitraryclosed space such as a vehicle, a train, a cargo, an airplane, a ship, asubmarine, or a tank. Further, when H₂O (moisture) is added thereto atthe time of generating plasma, more OH radicals and the like aregenerated, thereby improving the effect.

In addition, the present apparatus may be applied to air cleaning andcarbon monoxide poisoning prevention in case of fire in facilities suchas a communal facility, a building, a gym, an auditorium, a shoppingmall and a tunnel, thereby contributing to a lifesaving such asdetoxification in which the carbon monoxide is changed into the carbondioxide and smoke removal.

INDUSTRIAL APPLICABILITY

The present invention may be used as an ignition apparatus used in aheat engine such as a reciprocating engine, a rotary engine, a jetengine and a gas turbine, or a plasma equipment, for example.

The present invention may be used for an internal-combustion engine towhich the ignition apparatus according to the present invention issuitably applied.

The present invention may be used for an ignition plug that is suitablyapplied to the ignition apparatus according to the present invention.

The present invention may be used for a plasma equipment used in anenvironmental (an in-plant and an end-of-pipe) countermeasure field suchas decrease and reduction of hazardous effluents (CO₂, NO_(x) andunburnt hydrocarbon), volatile organic compounds (VOC), suspendedparticulate matters (PM), soot and the like or process and reuse of tar,sludge, and drainage, and a medical/hygiene field such as sterilization,pasteurization and cleaning technology.

The invention may be used for an exhaust gas degradation apparatus towhich the plasma equipment according to the present invention issuitably applied.

The present invention may be used for an ozonegenerating/sterilizing/disinfecting apparatus and an odor eliminatingapparatus to which the plasma equipment according to the presentinvention is suitably applied.

I claim:
 1. A plasma equipment comprising: a microwave oscillator forgenerating a predetermined microwave band; a microwave resonant cavityfor allowing the predetermined microwave band to resonate; microwaveradiation means for radiating the microwave into the microwave resonantcavity, wherein the microwave radiation means is a microwave radiationantenna having the shape and the size so as to form a strong electricfield of the microwave in a plasma generation field formed by themicrowave; plasma ignition means that makes partial discharge in gas inthe microwave resonant cavity and then induces plasma in the gas; andcontrol means for controlling the microwave radiation means and theplasma ignition means and a measurement unit for measuring thegeneration amount or emission intensity of OH radicals and O.sub.3generated by plasma generation, wherein the microwave radiation meansand/or the plasma ignition means process a result of the measurementunit in real time so as to provide the resultant to the control means.2. The plasma equipment according to claim 1, further comprisingmicrowave transmission means.
 3. The plasma equipment according to claim2, wherein the microwave transmission means is a coaxial cable.
 4. Theplasma equipment according to claim 2, wherein the microwavetransmission means is a waveguide.
 5. The plasma equipment according toclaim 1, wherein a magnetron for home electric appliances having anoscillation frequency of 2.45 GHz is used as the microwave oscillator.6. The plasma equipment according to claim 1, wherein the microwaveradiation means includes an ignition/discharge unit serving as themicrowave radiation means and the plasma ignition means, and themicrowave radiation means and the ignition/discharge unit are providedin an integrally formed insulator.
 7. The plasma equipment according toclaim 6, further comprising: a coaxial cable for transmitting themicrowave; a directional coupler for branching, isolating, and couplingthe microwave; and a regulator for regulating impedance of entiretransmission systems.
 8. A plasma equipment comprising: a microwaveoscillator for generating a predetermined microwave band; a microwaveresonant cavity for allowing the predetermined microwave band toresonate; microwave radiation means for radiating the microwave into themicrowave resonant cavity, wherein the microwave radiation means is amicrowave radiation antenna having the shape and the size so as to forma strong electric field of the microwave in a plasma generation fieldformed by the microwave; and plasma ignition means that makes partialdischarge in gas in the microwave resonant cavity and then inducesplasma in the gas; and wherein the plasma ignition means uses barrierdischarge which inserts an insulating material such as a dielectric bodybetween electrodes, corona discharge which forms a non-uniform electricfield, and pulse discharge which applies less than 1 .mu.s of shortpulse voltage.